1. Field of the Invention
The present invention relates to a liquid silicone rubber coating composition, which is an adhesive coating agent that can be used without dissolution in an organic solvent, and is ideal for air bags in which the bag portion is woven, and also relates to an air bag with a rubber coating layer comprising a cured product of such a composition.
2. Description of the Prior Art
In recent years, a variety of different silicone rubbers have been used as coating agents for fibers, and those coating agents are used on air bags and the like that are fitted to transportation vehicles such as automobiles. Some air bags are fabricated by overlaying two layers of plain weave base fabric, which have been coated on their respective inside surfaces with a rubber coating layer, bonding the peripheral sections of the two layers of base fabric together with an adhesive, and then stitching the adhesive layer (hereafter referred to as plain weave air bags). Furthermore, air bags in which the bag portion is formed by weaving, which do not require adhesive bonding (hereafter referred to as woven air bags), have also been proposed (see patent reference 1).
However, although woven air bags are compact, they have suffered from a number of problems. Because of their construction, woven air bags comprise the rubber coating layer on the outside surface, meaning that on inflation of the air bag, the inflator gas first contacts the base fabric surface, rather than contacting the rubber coating layer as is the case with plain weave air bags. As a result, if the types of coating agents that have been used with conventional plain weave air bags are applied to woven air bags, then the air bag is unable to be maintained in an inflated state for a constant period of time. Accordingly, the development of a coating agent that can be favorably used within woven air bags has been keenly sought.
A variety of silicone rubber coating agents have been proposed as solutions to the above problem (see patent reference 2 through patent reference 7), but all of these coating agents have required dilution of the agent with an organic solvent prior to use. Furthermore, liquid silicone rubber coating agents that do not require organic solvent dilution have also been proposed (see patent reference 8 through patent reference 11), but none of these has been able to satisfy all the requirements of good adhesion to fiber (the base fabric), favorable rubber strength, and good maintenance of the inflated state, which is required when the coating agent is applied to an air bag.    [Patent Reference 1] JP2-158442A    [Patent Reference 2] JP 5-25435A    [Patent Reference 3] U.S. Pat. No. 5,258,211    [Patent Reference 4] U.S. Pat. No. 5,208,097    [Patent Reference 5] JP7-70923A    [Patent Reference 6] EP 0 663 468 A1    [Patent Reference 7] U.S. Pat. No. 5,529,837    [Patent Reference 8] U.S. Pat. No. 5,877,256    [Patent Reference 9] U.S. Pat. No. 6,268,300    [Patent Reference 10] JP 2002-138249A    [Patent Reference 11] U.S. Pat. No. 6,369,184